Sounds like you're talking about the detent which almost all liner locks have, some even have double detents.TCR: one thing I noticed when the subject of the locking liner came up is that there is a small "nipple" on the inner surface of the liner and it falls into a groove on the base of the blade and acts to 'snap' the liner into place. This seems to make the liner even more secure against the base of the blade. Also the same nipple falls into a small indent when the blade is closed.